The wind-fueled fireball that injured seven Prince George’s County firefighters when it blew through the burning house they had just entered was “a freak occurrence,” a department spokesman, Mark Brady, said Saturday.

“Wrong place at the wrong time,” Prince George’s Fire Chief Marc S. Bashoor added, explaining how a basement fire Friday night suddenly turned a small Riverdale area house into something like a blast furnace.

Three firefighters remained hospitalized Saturday afternoon, although one had been cleared for release after being treated for injuries to his upper body and ribs and first-degree burns on his hands.

Ethan Sorrell, 21, and Kevin O’Toole, 22, were in critical but stable condition in the burn unit at Washington Hospital Center, Brady said. Sorrell sustained “burns to his airway,” and O’Toole suffered second- and third-degree burns over 40 percent of his body.

Four other injured firefighters were treated and released overnight.

The fire call came in at 9:11 p.m., authorities said. Within minutes, trucks from the Riverdale and Bladensburg volunteer fire departments arrived at the house in the 6400 block of 57th Avenue, just east of Kenilworth Avenue.

There was a car parked in the driveway, and the basement was burning.

Seven men from Company 807/Riverdale and from Company 809/Bladensburg entered through the front door, on the east side of the house, Bashoor said.

Strong winds were gusting out of the west at the time — “up to 40, 45 mph,” said the chief. They were blowing directly at — and into — the burning basement, which had a west-facing door.

The conditions nearly proved fatal.

“As soon as the guys opened the front door and advanced, it blew from the basement, up the steps and right out the front door,” Bashoor said. “It was like a blowtorch coming up the steps and out the door.”

The entire incident — “from the time they were in the door until they were burned” — took eight seconds, the chief said.

The firefighters inside the house “did everything they were trained to do,” he said, but they were essentially defenseless.

Eventually, another team of firefighters extinguished the fire, the cause of which is under investigation. Authorities estimated damage to the house, which was vacant, at $75,000.

On Saturday, as well-wishers from the region’s fire and EMS community streamed in and out of the hospital, Bashoor tried to make sense of what happened.

“Without that wind, the hot air and gases would have been venting out of the rear of the house,” he said. “The current of air essentially produced a chimney right up the steps and out the front door.”

He added: “It’s very unusual to have seven firefighters injured in a flash event at one time.”